<!DOCTYPE html5>
<html>
  <head>
    <title>js2600</title>
    <script type="text/javascript">

window.onload = function() {
var ctx = document.getElementById('tv').getContext('2d');
var d = ctx.getImageData(0, 0, 100, 100);
d.data[0] = 0;
d.data[1] = 0;
d.data[2] = 0;
d.data[3] = 255;
ctx.putImageData(d, 0, 0);
}

    </script>
  </head>
  <body>
    <canvas id='tv' height=100 width=100></canvas>
  </body>
</html>
